This invention relates to a process and apparatus for reclamation of batteries other than lead-acid batteries and more particular to reclamation and environmentally safe disposal of nickel cadmium, lithium, carbon-zinc, mercury, alkaline, metal hydride, etc. batteries.
Currently, there is considerable concern with the disposal of used batteries in industrial countries occasioned by the accumulation of batteries from those used in wrist watches to those used in diesel locomotives. Also, even with the increased use of rechargeable batteries, disposal still persists as a problem in many industrial countries.
Various processes have been proposed utilizing pyrolysis for reclaiming rubber tires, plastics, inorganic compounds and metals, such as, cadmium, lithium, mercury, etc. Processes dealing with the treatment of used rubber tires by pyrolysis to recover liquid and gaseous hydrocarbons and separate these from solid residue proliferate as described in various patents. Likewise, a number of pyrolysis processes are described for reclaiming waste metals containing coatings of organic insulation. Further, a number of processed have been proposed for recovery of metals used in various batteries.
U.S. Pat. No. 4,235,676, issued to Chambers discloses a process for reclamation and treatment of organic waste materials, such as, rubber automobile tires or industrial plastic waste or residential trash, which preferably has metal of inorganic matter removed therefrom, is passed through an elongated chamber by means of a screw conveyor with the temperature in the chamber maintained at 1100.degree. F. The vapors and gases are removed from the chamber by means of a vacuum with the vapors being condensed and the gases separated therefrom. The chamber is maintained free from air or oxygen.
U.S. Pat. No. 5,085,738, issued to Harris et al discloses a method of treating and recovery of organic waste material in an oxygen-free chamber filled with molten lead which is inclined to allow organic material with a lessor specific gravity than the lead to migrate through the molten lead to a higher portion of the chamber. The organic material from the chamber is recycled as fuel gas and the residual solids flow to a reservoir connected to the chamber. Carbon black is drawn into a receiver by a vacuum line located near the top of the reservoir and all the other residual solids flow over a reservoir wall.
U.S. Pat. No. 4,515,659, issued to Wingfield, Jr. et al discloses a process for improving the pyrolytic conversion of waste selected from rubber and plastic to low molecular weight olefinic materials by employing basis salt catalysts in the waste mixture. The salt catalysts comprise alkali or alkaline earth compounds and Wingfield, Jr. cites sodium carbonate as one.
U.S. Pat. No. 4,740,270, issued to Roy discloses a process for treatment of used rubber tires by vacuum pyrolysis in a reactor to produce liquid and gaseous hydrocarbons and solids. The pyrolysis is carried out in a temperature range of 360.degree. C. to about 415.degree. C. under sub-atmospheric pressure. The process is claimed to increase the yield of liquid hydrocarbons and lower the yield of gaseous hydrocarbons and carbonaceous material. The process produces hydrocarbon oils suitable for use as heating fluids.
U.S. Pat. No. 4,686,008, issued to Gibson discloses apparatus for thermal decomposition or pyrolysis of shredded vehicle tires. Undecomposed rubber, fiberglass, carbon and metal products are collected at the end of the pyrolysis chamber, and the gaseous products are separately collected and sent through a fractionator. The undecomposed materials are treated separately.
A number of processes are similar to that disclosed in U.S. Pat. No. 3,448,509, issued to O'Reilly disclose a process wherein a quantity of plastic-insulated wire is placed in a sealed air-tight chamber with limited air therein. The wire is heated in the chamber to a temperature to reduce the plastic to a crisp residue and to evolve gases from the plastic. The off-gases are then wet-scrubbed to remove undesired constituents and the crisp residue is ultimately removed from the wire.
U.S. Pat. No. 3,945,890, issued to Kemp discloses a process for decomposing organic and pseudo-organic materials into useable and reusable forms. Inorganic metals and salts are treated in the same convertor system. The materials are carried on a conveyor through a controlled atmosphere chamber virtually free of oxidizing agents. A negative pressure is maintained upstream of the chamber to collect liquid and gaseous vapor streams which are processed through successive stages of collection containers, condensers and gas scrubbers.
U.S. Pat. No. 4,091,825, issued to Baker discloses another pyrolysis process in which metallic scrap containing a coating of organic insulation is processed in a pressure pyrolysis vessel maintained at a pressure between 20 to 40 psi and in a temperature range of about 500.degree. to 1000.degree. F. depending on the type of insulation.
A number of processes describe the method or process of treating batteries to recover useful products. Such a process is described in U.S. Pat. No. 4,775,107, issued to Heng et al which discloses a process of crushing and then roasting batteries at a temperature of 500.degree. to 1000.degree. C. in an oxidizing atmosphere with volatilized mercury recovered from the off-gas. The roasted material is separated by sieving and magnetic separation which separates iron-containing scrap, and the residue containing magnesium, zinc and silver. Heng et al cites several processes for treating batteries.
U.S. Pat. No. 5,199,975 issued to Gunjishima et al discloses a method for recovering cadmium in used nickel cadmium batteries by heat treatment. The process discloses the purity of high cadmium by volatilizing cadmium in a non-oxidizing atmosphere.
U.S. Pat. No. 5,252,189 issued to Celi discloses a thermal mechanical treatment in a closed container at a temperature at which, with the assistance of mechanical pressure metal-plastic and metal-metal bonds are disrupted. Synthetic plastic parts and graphite electrodes are separated by physical methods, vaporized mercury is extracted and washed with sulphuric acid. A gas washing device for inert gas leaving the container employs sulphuric acid in which the vaporized mercury reacts forming mercury sulphate.
U.S. Pat. No. 4,913,064, issued to Volhardt discloses a general waste arrangement for the low temperature carbonization of waste material. The waste materials include household and industrial waste, as well as, chemical waste containing noxious matter and dioxines and furanes containing hazardous substances. The heating system is substantially corrosion free and hazardous gases are transformed into gases with a lower level of hazardous matter by directing the heating gas of the low temperature carbonization device and into a heat exchanger of a secondary incineration device with the heat exchanger being maintained at 1200.degree. C.
U.S. Pat. No. 5,284,503, issued to Bitler et al discloses a plasma arc furnace which pyrolyzes lead-contaminated soil and battery casing. The combustible gas along with volatilizes lead are transferred to and used a primary fuel in a conventional smelting furnace. The volatilized lead is thus transferred to the recovery and environmental equipment associated with smelting furnaces. The soil is converted into a non-toxic vitrified slag and may be crushed for use as roadway aggregate.